Skyrim Soul Gems Duplicate 2024
Step 1 : You need to create some item to enchant, iron dagger would be good.
Step 2 : Go to enchantment table and enchant your iron dagger with banish enchantment.
Step 3 : Buy all soul gems from vendor then sell all your enchantment iron dagger to them.
Reset the vendor after every transaction and repeat it many as you like.
This way you can increase several skill like Smithing, Enchanting, Speech.